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Abstract:

The present disclosure relates to the preparation and application of
conducting polymers nanoparticle composites. Specifically, the disclosure
relates to the preparation of polyaniline, or similar conducting
polymers, as polymer nanoparticles on substrates prepared by chemical
polymerization of aniline on the surface or inside the pores of the
substrate. Isolated polymerization, e.g. inside the pores, avoids the
formation of aggregate polyaniline nanoparticles. The process of the
present disclosure may be used for both inorganic and organic porous
solids that are water insoluble, acid resistant, and resistant to
oxidants such as ammonium persulfate. The conducting polymer nanoparticle
composites may be used in a variety of applications, including as
anticorrosion coatings.

Claims:

1. A conducting polymer nanoparticle composite comprising: (i) a
conducting polymer nanoparticle, and (ii) a substrate, wherein the
conducting polymer nanoparticle is contained on the surface of the
substrate.

2. The composite of claim 1, wherein the nanoparticle has a diameter of
about 3.5 nm to about 500 nm.

3. The composite of claim 1, wherein the substrate has a diameter of
about 250 nm to about 5000 nm.

4. The composite of claim 1, wherein the conducting polymer is selected
from the group consisting of substituted or unsubstituted polyaniline and
substituted or unsubstituted polypyrrole.

5. The composite of claim 4, wherein the substituted or unsubstituted
polyaniline has a structure of formula (I): ##STR00002## wherein
R1 and R2 are independently selected from the group consisting
of H, OH, COOH, I, F, NO2, NH2, substituted or unsubstituted
C1-C6 alkyl, and substituted or unsubstituted C1-C6
alkoxy groups; and m is 0 to 4.

6. The composite of claim 1, wherein the substrate is selected from the
group consisting of a silica bead, a pigment, an inorganic solid and an
organic solid, and wherein the substrate is substantially insoluble in an
aqueous or semi-aqueous solution and stable in a dilute acidic solution.

11. A method of preparing a conducting polymer nanoparticle composite
comprising (i) providing a substrate (ii) combining the substrate with a
solution including a monomer of a conducting polymer to form a
suspension, (iii) mixing the suspension to wet the substrate with the
solution, wherein at least a portion of the monomer interacts with the
surface, (iv) separating any excess bulk solution from the wetted
substrate, and (v) polymerizing the monomer.

12. A corrosion inhibiting coating composition for coating a metal
substrate comprising a topcoat layer, and a primer layer having a
conducting polymer nanoparticle composite, wherein the composite
includes: (i) a conducting polymer nanoparticle, and (ii) a substrate,
wherein the conducting polymer nanoparticle is contained on the surface
of the substrate.

13. The coating composition of claim 1, wherein the primer layer includes
about 0.5% to about 50% weight percent of conducting polymer nanoparticle
composite.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application
Ser. No. 61/724,542 filed Nov. 9, 2012, the entire contents of which is
incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present disclosure relates to the preparation and application
of conducting polymer nanoparticle composites. Specifically, the present
disclosure relates to the preparation and application of conducting
polymers as nanoparticles in or on substrates (i.e, conducting polymer
nanoparticle composites).

[0004] Unfortunately, conducting polymers, such as polyaniline and
polypyrrole, have poor mechanical properties that make them difficult to
process into meaningful end products. Due to their poor processability,
manufacturing costs, material inconsistencies, and poor solubility in
solvents, conductive polymers have few large-scale applications.

[0005] A need exists for a new method to prepare unique compositions of
conductive polymers that overcome their poor mechanical properties and
utilize these materials in diverse applications.

SUMMARY OF THE INVENTION

[0006] The present disclosure relates to methods of preparing conducting
polymer nanoparticle composites that may be dispersed in a matrix, and
compositions comprising the same. These conducting polymer nanoparticle
compositions may be formed into high performance novel materials for
application in many industrial fields.

[0007] In one embodiment, the present disclosure relates to a conducting
polymer nanoparticle composite comprising a conducting polymer
nanoparticle, and a substrate, wherein the conducting polymer
nanoparticle is contained on the surface of the substrate, as well as
articles containing the same.

[0008] In another embodiment, the present disclosure relates to a method
of preparing a conducting polymer composite comprising providing a
substrate, combining the substrate with a solution including a monomer of
a conducting polymer to form a suspension, mixing the suspension to wet
the substrate with the solution, wherein at least a portion of the
monomer interacts with the surface, separating any excess bulk solution
from the wetted substrate, and polymerizing the monomer.

[0009] In a further embodiment, the present disclosure relates to a
corrosion inhibiting coating composition for coating a metal substrate
comprising a topcoat layer, and a primer layer having a conducting
polymer nanoparticle composite, wherein the composite includes a
conducting polymer nanoparticle, and a substrate, wherein the conducting
polymer nanoparticle is contained on the surface of the substrate.

[0011] Described herein is a composition containing a conductive polymer
nanoparticle composite, and methods of preparing the same. The conductive
polymer nanoparticle composites can be utilized in many diverse
applications. For instance, the present disclosure relates to a unique
preparation method for conductive polymer nanoparticle composites as well
as the application of conductive polymers as anticorrosion pigments in
coatings.

[0012] In one embodiment, the present disclosure relates to a conducting
polymer nanoparticle composite comprising a conducting polymer
nanoparticle, and a substrate, wherein the conducting polymer
nanoparticle is contained on the surface of the substrate.

[0013] As used herein, the term "conducting polymer" refers to
intrinsically conducting polymers, or ICPs, which include organic
polymers that conduct electricity. Conducting polymers may have metallic
conductivity or may be useful as semiconductors. Examples of conducting
polymers include polyaniline (PAn) and polypyrrole (Ppy).

[0014] The conducting polymer may be any polymer known to one skilled in
the art as a conducting polymer. For example, the conducting polymer may
be substituted or unsubstituted polyaniline, substituted or unsubstituted
polypyrrole, or combinations thereof.

[0015] The aniline monomer used to make the substituted or unsubstituted
PAn can be un-substituted aniline or substituted aniline having a
structure of formula (I):

##STR00001##

[0016] wherein R1 and R2 are independently selected from the
group consisting of H, OH, COOH, I, F, NO2, NH2, substituted or
unsubstituted C1-C6 alkyl, and substituted or unsubstituted
C1-C6 alkoxy groups; and m is 0-4.

[0017] The pyrrole monomer used to make the substituted or unsubstituted
Ppy can be un-substituted pyrrole or substituted pyrrole, such as
N-methylpyrrole, C4H4NCH3.

[0018] As used herein, the term "nanoparticle" refers to a polymer
particle having one or more dimensions (e.g. diameter) measuring about
the order of 100 nm or less. The size and shape of the nanoparticle may
vary. The present disclosure relates to a method to obtain nanoparticles
by limiting agglomeration. For example, the morphological subunit of
polyaniline, for example, is small, such as about a 3.5 nm particle unit.
These units may agglomerate to bigger particles. Preferably, the polymer
nanoparticles are between about 3.5 nm and about 500 nm, and more
preferably between about 10 nm and about 100 nm.

[0019] The substrate may be any known substrate particle known to one
skilled in the art as a suitable substrate. For example, the substrate
may be a silica bead, a pigment, an inorganic solid, an organic solid, or
combinations thereof.

[0020] The substrate may also be substantially insoluble in an aqueous or
semi-aqueous solution, and stable in a dilute acidic solution. The
substrate should be able to remain insoluble during preparation in the
polymerization solution (e.g. a dilute acidic aqueous or semi-aqueous
solution). In one embodiment, the substrate is water insoluble. Suitable
inorganic solids for use as a substrate include aluminas, silicas,
alumina-silicas, zeolites, etc. Suitable organic/polymer solids for use
as a substrate include synthetic rubber, phenol formaldehyde resin (or
Bakelite®), neoprene, nylon, polyvinyl chloride (PVC or vinyl),
polystyrene, polyethylene, polypropylene, polyacrylonitrile, PVB,
silicone, DER® 680-20, cation exchange resin C-249, Nylon 6,6 resin
and 3GT, etc. Suitable pigments for use as a substrate include talc,
barium sulfate, titanium dioxide, mica, calcium borosilicate,
phosphosilicates, molybdate pigments, barium metaborate, zinc phosphate,
etc.

[0021] In another embodiment, the substrate is acid resistant. In a
further embodiment, the substrate is oxidant resistant. For example, the
substrate does not substantially degrade in the presence of an oxidant,
such as ammonium persulfate.

[0022] The substrate may also be a porous solid. The conducting polymer
nanoparticle may be at least partially inside a pore on the porous solid.
The surface area of a substrate particle includes its geometric surface
area and the area of its pore wall. The pore diameter may be small to
limit the aggregation of the polymer nanoparticles when monomers
polymerize inside the pores. The total pore value of a porous solid is V
(cc/g), the specific surface area is S (m2/g), and the average pore
diameter is R. R can be estimated as R=2V/S. For example, a porous solid
with a total pore value of about 0.3 cc/g (V˜0.3 cc/g) and a
specific surface area of about 5 m2/g (S˜5 m2/g) has an
average pore diameter of about 120 nm. For a porous solid with a surface
area as low as 1 m2/g, the average pore diameter is 600 nm.

[0023] Preferably, the porous solid of the present disclosure may have a
total pore value of about 0.05 cc/g to about 0.80 cc/g. More preferably,
the total pore value may be about 0.1 cc/g to about 0.50 cc/g. The porous
solid may also have a preferred specific surface area of about 0.5
m2/g to about 1200 m2/g. More preferably, the preferred
specific surface area may be about 0.5 m2/g to about 50 m2/g.
Finally, the porous solid of the present disclosure may have an average
pore size of about 5 nm to about 5000 nm, and more preferably about 50 nm
to about 2000 nm.

[0024] Porosity or void fraction is a measure of the void (i.e., "empty")
spaces in a material, and is a fraction of the volume of voids over the
total volume, between 0-1, or as a percentage between 0-100%. Porous
substrates of the present disclosure may have a porosity between about 5%
to about 70%, and preferably between about 10% and about 50%.

[0025] The average particle size of the substrate particles is preferably
smaller than about 80 mesh. Substrate particles may be screened to remove
bigger particles by passing the particles through an about 80 to 100 mesh
sieve. In one embodiment, the average diameter of the substrate particles
is between about 250 nm and about 5000 nm. Preferably, the average
diameter of the substrate particles is between about 450 nm and about
3000 nm. More preferably, the average diameter of the substrate particles
is between about 500 nm and about 2000 nm.

[0026] The substrate may also be a solid with a non-smooth surface. With
regard to a porous solid or solid with a non-smooth surface, the
conducting polymer nanoparticle may be contained in or on the surface of
the substrate. The conducting polymer may be contained on the surface and
inside, or partially inside, the porous solid or non-smooth surface.

[0027] The substrate may have local areas where monomers of a conducting
polymer are present when the substrate is wetted with a solution having
such monomers. Upon polymerization, these monomers may form discrete
nanoparticles. For example, when a porous solid is wetted with a solution
containing a monomer of a conducting polymer, the monomer may collect
inside the pores of the porous solid. Upon polymerization, monomers form
a conducting polymer nanoparticle within the pore.

[0028] The amount of conducting polymer nanoparticle in the composite may
vary depending on the polymer, the substrate and the application or
article for use with. Preferably, the weight percent of conducting
polymer nanoparticle in the composite is between about 0.1% and about
50%. More preferably, the weight percent of conducting polymer
nanoparticle in the composite is between about 0.5% and about 25%. Even
more preferably, the weight percent of conducting polymer nanoparticle in
the composite is between about 3% and about 15%.

[0029] Broadly, the conductive polymer nanoparticle composites may be
prepared by immersing a particle in a monomer solution and initiating
polymerization. The monomers which are adsorbed on the particle surface
or are in the solution close to the surface may polymerize and
precipitate on the surface as polymer nanoparticles. If a sufficient
amount of bulk solution remains, the monomers in the bulk solution may
polymerize and aggregate with the polymer nanoparticles on the surface.
General polymerization from the bulk solution may result in a build up of
an aggregated polymer layer around the entire particle surface. The
present disclosure utilizes polymerization with limited or no bulk
solution to form a composite of polymer nanoparticles on and/or within
the solids particles. It have been discovered that formation of
substantially non-contiguous conducting polymer nanoparticles on the
surface of a substrate is preferred over the formation of conducting
polymer networks in solution or the formation of conducting polymer
networks as a substantially contiguous layer on the substrate.

[0030] In one embodiment, the present disclosure relates to a method of
preparing a conducting polymer nanoparticle composite comprising
providing a substrate, preferably with a non-smooth or porous surface,
combining the substrate with a solution including a monomer of a
conducting polymer to form a suspension, mixing the suspension to wet the
substrate with the solution, wherein at least a portion of the monomer
interacts with the porous or non-smooth surface, separating any excess
bulk solution from the wetted substrate, and polymerizing the monomer.

[0031] Wetting the substrate may allow the monomer to interact with the
substrate surface. For a non-smooth or porous solid, wetting the solid
allows the monomer to enter into the non-smooth areas or pores of the
solid. These areas may collect a greater proportion of the monomer than
other smooth or non-porous regions of the surface.

[0032] Any remaining excess bulk solution of monomer may be removed from
the wetted substrate. Removal of the bulk solution limits the amount of
monomer outside of the surface irregularities. It has been found that
limiting the amount of monomer in the bulk solution or on the smooth or
non-porous surface of a substrate assists the formation of conducting
polymer nanoparticles on the substrate surface. The removal of excess
monomer by removal of the bulk solution and the non-uniform distribution
of the monomer on the surface of the substrate limit the formation of
aggregated conducting polymer particles or a contiguous over layer of
conducting polymer on the substrate surface. Limiting aggregated
conducting polymer particles reduces the precipitate of such particles on
the surface of the substrate and the formation of a contiguous conducting
polymer over-layer.

[0033] Polymerization of the monomer may be initiated by any means known
to one skilled in the art. For example, polymerization of the conducting
monomers may be initiated by oxidation. Suitable oxidizing agents include
ammonium persulfate, potassium dichromate, potassium iodate, ferric
chloride, potassium permanganate, potassium bromate, and potassium
chlorate.

[0034] For example, an acidic solution of aniline may be combined with a
porous pigment powder. The combination may be mixed until the powder is
completely wet with solution. Preferably, the aniline is collected in the
pores of the pigment. Any remaining bulk solution may be removed from the
mixture. An oxidant solution may then be mixed with the combination. The
oxidant solution functions to initiate polymerization of the monomer. The
mixture may be stirred for an addition time, e.g. 30 minutes. The mixture
may be rinsed with distilled water, filtered and dried. The resulting
product is a pigment powder having conducting polymer nanoparticles
contained within, or partially within, its pores.

[0035] The pH of the acidic aniline solution may be less than about 4. The
acidic pH may be obtained using any acid including inorganic or organic
acids, such as phosphoric acid, hydrochloric acid, sulphuric acid, nitric
acid, acetic acid, organic sulphonic acid, for example para-toluene
sulphonic acid, dodecel benzene sulphonic acid, methane sulphonic acid,
benzene sulphonic acid.

[0036] Without being bound by any particular theory, it is believed the
monomers collect in the pores, or are absorbed into the pores, by
capillary effect. The amount of monomer collected in the pores may be
determined by knowing the concentration of monomer in solution and
measuring the amount of solution absorbed into the pores.

[0037] The conducting polymer nanoparticles composites may be used in many
diverse applications and on many different articles. The conducting
polymer nanoparticle composites may be used as anticorrosive primer,
electrostatic dissipation coatings, electromagnetic interference
shielding, static resistant fibers or textiles, conductive ink or toner,
or as conductive adhesives. The conducting polymer nanoparticle
composites may be used with articles such as windmills, transportation
infrastructure of highways, bridges, containers and storage tanks,
off-shore oil platforms, metal structures, automobiles, rail cars, and
petrochemical plants, military aircraft and missiles, commercial
passenger aircrafts, cargo holds and cargo tanks, decks, and ships.

[0038] For example, the conducting polymer nanoparticle composites may be
used in anticorrosive coatings. Unextracted metal usually exists in its
stable oxidized state as an ore. Extracted metal has a tendency to react
with its environment and form a corresponding oxide. This process of
oxide formation leads to deterioration and is called corrosion. Certain
conditions, such as the existence of aggressive anions, can accelerate
corrosion. Chloride and sulfate ions are two of the more aggressive
anions and their presence will accelerate the corrosion of metal when
contacted with a metal surface.

[0039] The use of an organic coating on a metal substrate is one of the
most important approaches to reduce corrosion. Such organic coatings
often contain an anticorrosive pigment to improve corrosion protection.
An anticorrosion coating system usually consists of multiple coating
layers including a primer layer; one or more inter layer(s), and a
topcoat layer.

[0040] Anticorrosive pigments include inhibitive pigments, sacrificial
pigments, barrier pigments and cation exchange pigments. Inhibitive
pigments include chromates, phosphates, molybdates, borates, red lead
etc. Sacrificial pigments include metallic zinc. Barrier pigments include
aluminum flake and steel flake. For a review of inhibitive, sacrificial
and barrier pigments see Alan Smith, "Inorganic Primer Pigments"
Published by Federation of Societies for Coating Technology.
Philadelphia, Pa., 19107. Conducting polymer nanoparticles composites, as
well as cation exchange pigments, however, are preferred anticorrosive
materials because they can be formulated with less toxic and less
carcinogenic effects.

[0041] Anticorrosive coatings having a conducting polymer nanoparticles
composite may be able to prevent oxygen, water, and aggressive anions in
the environment from arriving at or near, or contacting, the substrate
metal surface and degrading or corroding the metal.

[0042] Organic coatings on a metal substrate may be used to reduce
corrosion. These coatings usually consist of multiple layers including a
primer layer; inter layer(s), and a topcoat layer ("topcoat"). The primer
layer is the layer directly coated on the metal surface. Primer layers
may provide adhesion of the overall coating to the metal surface. The
primer layer may consist of a vehicle (e.g., resin binder), a solvent
(except in 100% solids coatings), a pigment, a filler (except for clear
coatings) and additives. The primer layer excludes the normal washing,
cleaning and other pre-treatment steps or applications used to prepare a
corrodible metal substrate for coating. For example, the primer layer
excludes Bonderite® 1303 which converts the metal surface to a
nonmetallic amorphous, complex oxide layer. The surface is still an
inorganic layer as opposed to an organic coating layer, as described
herein.

[0043] Examples of primer layers include epoxy primers, organic zinc rich
primers, inorganic zinc rich primers, powder coating primers and wash
primers. Epoxy primers may be two-pack materials utilizing epoxy resins
and either a polyamide or polyamine curing agents. They may be pigmented
with a variety of inhibitive and non-inhibitive pigments. Zinc phosphate
epoxy primers are the most frequently encountered.

[0044] The coatings may also optionally contain one or more inter layers
between the primer layer and topcoat. Most coatings, including
automotive, aerospace, aircraft and marine coatings, contain multiple
layers including inter layers. The inter layer may serve as a barrier in
the coating system, as well as adding film thickness or "build."
Generally, the thicker the coating the longer the life. The inter layer
may also provide adhesion between the primer layer and the topcoat. Some
inter layers have special functions, for example, the inter layer of an
automotive coating may provide color.

[0045] Inter layers may consist of a vehicle (e.g., resin binder), a
solvent (except in 100% solids coatings), a pigment, a filler (except for
clear coatings) and additives. Most inter layers are an epoxy inter
layer.

[0046] The topcoat is the outmost layer of the coating composition. The
topcoat is often used to provide a required appearance and surface
resistance to the system. Depending on the conditions of exposure, it may
also provide the first line of defense against weather and sunlight, open
exposure, condensation (as on the undersides of bridges), highly polluted
atmospheres, impact and abrasion, and bacteria and fungi.

[0047] Topcoats may consist of a vehicle (e.g., resin binder), a solvent
(except in 100% solids coatings), a pigment, a filler (except for clear
coatings) and additives. Topcoats differ from primer layer and inter
layers, in part, due to their function and specific additive that may be
present in the topcoats to achieve the specific functions. Examples of
topcoat formulations may include epoxy topcoats, polyurethane topcoats,
alkyd topcoats, water borne topcoats, high temperature resistant
topcoats, topcoat of powder coatings and PVC topcoats.

[0048] The coating composition of the present disclosure has at least two
layers, a primer layer and a topcoat layer. The primer layer may contain
at least one conducting polymer nanoparticle composite and may function
to prevent or reduce corrosion of the underlying material. The topcoat
layer may be any distinct layer above the primer layer which acts a
topcoat layer or is traditionally considered a topcoat layer. The quality
and quantity of the conducting polymer nanoparticle composite in the
primer is sufficient to allow the primer to prevent or reduce corrosion
of the underlying material. The incorporation of at least one conducting
polymer nanoparticle composite in the primer layer may inhibit anions
found in the environment from interacting with the substrate.
Accordingly, the primer layer having at least on conducting polymer
nanoparticle composite may provide substantial anticorrosive protection
to the metal substrate, particularly in the environments of aggressive
anions.

[0049] In one embodiment, the present disclosure relates to a corrosion
inhibiting coating composition for coating a metal substrate comprising a
topcoat layer, and a primer layer having a conducting polymer
nanoparticle composite, wherein the composite includes a conducting
polymer nanoparticle, and a substrate, wherein the conducting polymer
nanoparticle is contained on the surface of the substrate.

[0050] The substrate to be protected may be any metal or metal containing
material or composite that is subject to corrosion, particularly by
aggressive anions. The substrate may include steel, galvanized steel,
aluminum, aluminum alloys, zinc, zinc alloys, magnesium, and magnesium
alloys.

[0051] The primer layer may have variable amounts of conducting polymer
nanoparticle composite depending on the type of polymer, substrate,
application or article for use with. Preferably, the weight percent of
conducting polymer nanoparticle composite in the primer layer is about
0.05% to about 50%. More preferably, the weight percent of conducting
polymer nanoparticle composite in the primer layer is about 0.5% to about
35%. Even more preferably, the weight percent of conducting polymer
nanoparticle composite in the primer layer is about 0.5% to about 15%.

[0052] The inter layer(s) and/or the topcoat layer may also contain a
conducting polymer nanoparticle composite or other anticorrosive
compound. The anticorrosive compound may also be in the primer layer. The
conducting polymer nanoparticle composite or other anticorrosive compound
may be any known in the art to provide anticorrosion resistance. The
anticorrosive compound may be the same or different with respect to each
other or with respect to the conducting polymer nanoparticle composite in
the primer layer. The amount of anticorrosive compound in the primer,
inter layer(s) and/or the topcoat layer may range from about 0.05 to
about 50 weight percent in each layer. Preferably, the amount may range
from about 3 to about 35 weight percent in each layer. In some
embodiments, a conducting polymer nanoparticle composite or other
anticorrosive compound may be present in both primer layer and topcoat
layer, both the primer layer and an inter layer, or the primer layer, an
inter layer and the topcoat layer. In other embodiments, the inter
layer(s) and topcoat may also be free or substantially free of other
traditionally considered corrosion inhibitors.

[0053] The coating materials may be applied to form a coating having an
average thickness from about 0.1 to about 6 mils, preferably from about
0.2 to about 3 mils.

[0054] All references cited in this disclosure are incorporated by
reference in their entirety.

EXAMPLES

[0055] The present invention is further defined in the following Examples.
It should be understood that these Examples, while indicating preferred
embodiments of the invention, are given by way of illustration only. From
the above discussion and these Examples, one skilled in the art can
ascertain the essential characteristics of this invention, and without
departing from the spirit and scope thereof, can make various changes and
modifications of the invention to adapt it to various uses and
conditions.

[0056] Examples 1 through 8 demonstrate how to make specific conducting
polymer nanoparticle composites. Examples 9-11 demonstrate the use of the
composites as anticorrosion pigments.

Example 1

Preparation of Polyaniline on Talc Powders

[0057] 6 g of p-toluensulfonic acid monohydrate (>98% Lot & filling
Code 133665 22507418 Fluka) was dissolved in 45 g of distilled water to
form a PTSA solution. Then, 2.0 g of aniline (>99% Batch 127K0669,
SIGMA) was dissolved in the PTSA solution. The acidic aniline solution
was mixed with 98 g of talc powders having a median diameter of about 1.8
microns (Mistron ultramix Lot T08192, Imerys) and stirred until the
mixture was homogeneously wetted and there was no solution left as bulk
solution. 1.3 g of ammonium persulphate (Purified, Science Lab) was
dissolved in ˜10 g distilled water, and then mixed with the wet
powders. The mixture was stirred until the color of the powder changed to
light green. The powders were rinsed with distilled water, the aqueous
liquor filtered off and the powders dried at 50-60° C. to produce
the product.

Example 2

Preparation of Polyaniline on Titanium Dioxide

[0058] 3.6 g of p-toluensulfonic acid monohydrate (>98% Lot & filling
Code 133665 22507418 Fluka) was dissolved in 46 g of distilled water
(PTSA solution). Then, 2.5 g of aniline (>99% Batch 127K0669, SIGMA)
was dissolved in the PTSA solution. The acidic aniline solution was mixed
with 97.5 g of titanium dioxide (Ti-Pure 931, median diameter is 0.55
microns, DuPont Co.) and stirred until the mixture was homogeneously
wetted and there was no solution left as bulk solution. 1.5 g of ammonium
persulphate (Purified, Science Lab) and 3 g of p-toluensulfonic acid
monohydrate (>98% Lot & filling Code 133665 22507418 Fluka) was
dissolved in ˜20 g distilled water, and then mixed with the wet
powders. The mixture was stirred until the color of the powder changed to
light green. The powders were rinsed with distilled water, the aqueous
liquor filtered off and the powders dried at 50-60° C. to produce
the product.

Example 3

Preparation of Polyaniline on Barium Sulfate

[0059] 7.9 g of p-toluensulfonic acid monohydrate (>98% Lot & filling
Code 133665 22507418 Fluka) was dissolved in 40 g of distilled water
(PTSA solution). Then, 2.0 g of aniline (>99% Science Stuff Inc., Lot
#107501) was dissolved in the PTSA solution. The acidic aniline solution
was mixed with 198 g of barium sulfate (Exbar4, Excalibar Minerals Inc.)
and stirred until the mixture was homogeneously wetted and there was no
solution left as bulk solution. 1.8 g of ammonium persulphate
(ScienceLab.com Inc.) dissolved in ˜5 g distilled water, and then
mixed with the wet powders. The mixture was stirred until the color of
the powder changed to light green. The powders were rinsed with distilled
water, the aqueous liquor filtered off and the powders dried at
50-60° C. to produce the product.

Example 4

Preparation of Polyaniline on Epoxy Resin D.E.R.® 680-20

[0060] 1 g of sulfuric acid (3M) was dissolved in 10 g of distilled water.
Then, 1.0 g of aniline (>99% Science Stuff Inc., Lot #107501) was
dissolved in the acid solution. The acidic aniline solution was mixed
with 20 g of D.E.R.® 680-20 epoxy resin powder (˜80 mesh) (Dow
Chemical Co.) and stirred until the mixture was homogeneously wetted and
there was no bulk solution left. 3 hours later, dissolved 0.5 g of
ammonium persulphate (ScienceLab.com Inc.) in ˜5 g water, and then
mixed with the wet powders. The mixture was stirred for 1 hour, and the
color of the powder changed to dark green. The powders were rinsed with
200 ml distilled water, the aqueous liquor filtered off and the powders
dried at 50-60° C. to produce the product.

Example 5

Preparation of Polyaniline on Epoxy Resin D.E.R.® 611

[0061] 8 g of sulfuric acid (3M) was dissolved in 66 g of distilled water.
Then, 3.0 g of aniline (>99% Science Stuff Inc., Lot #107501) was
dissolved in the acid solution. The acidic aniline solution was mixed
with 97 g of D.E.R.® 680-20 epoxy resin powder (˜80 mesh) (Dow
Chemical Co.) and stirred until the mixture was homogeneously wetted and
there was no solution left as bulk solution. Dissolved 2 g of ammonium
persulphate (ScienceLab.com Inc.) in ˜5 g water, and then mixed
with the wet powders. The mixture was stirred for 1 hour, and the color
of the powder changed to dark green. The powders were neutralized with
14.0 g of NaOH solution (20 wt. %), then rinsed with 200 ml distilled
water, the aqueous liquor filtered off and the powders dried at
50-60° C. to produce the product.

Example 6

Preparation of Polyaniline on Cation Exchange Resin C-249

[0062] 2 g of aniline (>99% Science Stuff Inc., Lot #107501) dissolved
in 5.5 ml of 6N hydrochloric acid (Carolina Biological Supply Co.). The
acidic aniline solution was mixed with 8 g of C-249 resin powder (Batch
PA13C1, powder Lanxess Sybron Co.). Stirred until the mixture was
homogeneously wetted and there was no bulk solution left. Dissolved 1.5 g
of ammonium persulphate (ScienceLab.com Inc.) in 6 g distilled water, and
then mixed with the wet powders. The color of the mixture was immediately
changed to dark green. Continued the stirring for 30 minutes and rinsed
the powder with 20 ml distilled water, the aqueous liquor filtered off
and the powders dried at 50-60° C. to produce the product.

Example 7

Preparation of Polyaniline on Nylon-6,6 Resin

[0063] 6.5 ml of 6N hydrochloric acid (Carolina Biological Supply Co) was
dissolved in 8 g of distilled water. Then, 2.5 g of aniline (>99%
Science Stuff Inc., Lot #107501) was dissolved in the acid solution. The
acidic aniline solution was mixed with 50 g of Nylon 6,6 resin powder
(˜80 mesh) and stirred until the mixture was homogeneously wetted
and there was no bulk solution left. Dissolved 1.5 g of ammonium
persulphate (ScienceLab.com Inc.) in 6 g distilled water, and then mixed
with the wet powders. The mixture was stirred for 1 hour, and the color
of the powder changed to dark green. Rinsed the powder with 100 ml
distilled water, the aqueous liquor filtered off and the powders dried at
50-60° C. to produce the product.

Example 8

Preparation of Polyaniline on 3GT Polyester Resin

[0064] 6.5 ml of 6N hydrochloric acid (Carolina Biological Supply Co) was
dissolved in 6 g of distilled water. Then, 2.5 g of aniline (>99%
Science Stuff Inc., Lot #107501) was dissolved in the acid solution. The
acidic aniline solution was mixed with 50 g of 3GT polyester resin powder
(˜80 mesh) and stirred until the mixture was homogeneously wetted
and there was no bulk solution left. Dissolved 1.5 g of ammonium
persulphate (ScienceLab.com Inc.) in 6 g distilled water, and then mixed
with the wet powders. The mixture was stirred for 1 hour, and the color
of the powder changed to dark green. Rinsed the powder with 100 ml
distilled water, the aqueous liquor filtered off and the powders dried at
50-60° C. to produce the product.

Example 9

Preparation of Epoxy Primer Using the Composite of Polyaniline/Talc as
Anticorrosion Pigment

[0065] Part A:--The following materials are mixed together and fully
blended in a 300 mL ceramic jar ball mill overnight:

[0067] Parts A and B are mixed together in a 1 to 0.22 ratio (wt.) of A to
B. After 30 minute of the mixing, the mixture was used as a primer to
coat cold rolls steel (CRS) panels. The size of the panels is 7.5
cm×7.5 cm×0.08 cm. The panels are not pretreated before
application of the primer paint. A wire-wound rod of 100 um (BYK
additives & Instruments) was used to apply the primer paint on the
substrates. The coated panels are dried at RT for several hours. The
thickness of the dried primer layer is approximately 40 micrometers on
the steel panels.

Example 10

Preparation of Wash Primer Using the Composite of Polyaniline/Talc as
Anticorrosion Pigment

[0068] The following materials are mixed together and fully blended in a
300 ml ceramic jar ball mill overnight:

[0070] Parts A and B are mixed together in a 1 to 0.35 ratio (wt.) of A to
B. After 30 minute of the mixing, the paint material was used as a primer
to coat cold rolls steel (CRS) panels and aluminum panels (Q panel Co.).
The size of the panels is 7.5 cm×7.5 cm×0.08 cm. The panels
are not pretreated before application of the primer paint. A wire-wound
rod of 100 um (BYK additives & Instruments) was used to apply the primer
paint on the substrates. The coated panels are dried at RT for one hours.
The thickness of the dried primer layer is approximately 15 micrometers
on the steel panels.

Example 11

Preparation of Waterborne Primer Using the Composite of Polyaniline/Talc
as Anticorrosion Pigment

[0071] Part A--The following materials are mixed together and fully
blended in a 300 ml ceramic jar ball mill overnight:

[0073] Parts A and B are mixed together in a 1 to 0.21 ratio (wt.) of A to
B. After the mixing, the paint material was used as a primer to coat cold
rolls steel (CRS) panels and aluminum panels (Q panel Co.). The size of
the panels is 7.5 cm×7.5 cm×0.08 cm. The panels are not
pretreated before application of the primer paint. A wire-wound rod of
100 um (BYK additives & Instruments) was used to apply the primer paint
on the substrates. The coated panels are dried at RT for several hours.
The thickness of the dried primer layer is approximately ˜35
micrometers on the steel panels.

Example 12

Apply Topcoat on the Primers of Example 9-Example 11

[0074] A commercially available paint material IMRON® 2.1 HG-C®
(DuPont Co.) was used as the topcoat paint for the primers of Example
9-Example 11. 3 parts of IMRON® 2.1 HG-C® were mixed with 1 part
of IMRON® FG-1333® by stirring. A wire-wound rod of 100 um (BYK
additives & Instruments) was used to apply the topcoat on the primers.
The topcoat was dried at RT overnight. The thickness of the topcoat layer
was approximately 45 micrometers on the surface of primers.

Example 13

Electrochemical Characterization of the Primer--Topcoat Systems of Example
12

[0075] The topcoat-primer coating systems of Example 12 were characterized
by Electrochemical Impedance Spectroscopy (EIS). The EIS measurement was
using a Gamry Instruments model reference 600®
Potentiostat/Galvanostat with corrosion system software. A
three-electrode cell was setup. The counter electrode was a graphite rod
(r˜3 mm), the reference electrode was a saturated calomel electrode
(SCE), and the working electrode was the coated metal panel of which the
exposed area to the electrolyte solution was ˜3.5 cm2. The
electrolyte solution was a 3.5 wt. % aqueous solution of sodium chloride.
Electrochemical Analyst software was used to get the EIS data. An
important EIS data is the pore resistance Rpo which is the resistance for
ionic transport through a coating layer. A coating that maintained a
resistance of 108 Ohm cm2 provides good corrosion protection
while one having a resistance below 106 Ohm cm2 does not.

[0076] The Bode plots of EIS are show on FIG. 1. The following table shows
the pore resistance, or Rpo value, for the topcoat-primer systems
immersed in 3.5 wt. % sodium chloride solution.